title: Extracranial stereotactic radioablation: physical principles.
mesh_terms: D005240:Feasibility Studies; D008433:Mathematics; D018787:Radiation Oncology / Q000379:methods*; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy; D013238:Stereotaxic Techniques; D013679:Technology, Radiologic